1. Field of the Invention
The present invention relates to a wireless communication system for video packet transmission, and more particularly, to a wireless communication system for determining whether to transmit a video packet considering the degree of importance of video data.
2. Description of the Related Art
In general, in wireless communication systems, moving picture information for video packet transmission is encoded through a video codec and encoded data is transmitted through a wireless channel with information items such as a header added thereto, after passing through the respective layers of the wireless communication system.
FIG. 1 is a block diagram of a conventional wireless transmission system for video packet transmission. The wireless transmission system shown in FIG. 1 includes a video encoder 100, a packetizing unit 102, and a wireless transmitter 104. The video encoder 100 encodes a moving picture to be transmitted. The packetizing unit 102 divides the encoded data in the form of packets and adds information items such as the header to each packet. The wireless transmitter 104 synchronously transmits video packet data through the wireless channel. In this case, the video encoder 100 must generate video data at a coding rate which is smaller than an allowed channel bandwidth. This is because information items such as header are added to the data transmitted through the channel in the lower layers of the wireless communication system, that is, the packetizing unit 102 and the wireless transmitter 104. Therefore, the video encoder 100 generates video data which is suitable for the allowed channel bandwidth.
However, when the video data are required to be transmitted at a transmission rate which is larger than the bandwidth of the channel, namely, when a large amount of video data is required to be transmitted, a certain amount of data is buffered and transmitted in order for the bandwidth of the channel to handle the amount of data. In this way, the buffered data is delayed.
In order to solve the above problem, a method in which more channel bandwidths are given should be provided. However, this method needs more transmission expenses since the amount of use of the channel increases.
To solve the above problem, it is an object of the present invention to provide a wireless transmission system for video packet transmission capable of determining the degree of importance of encoded video data and determining the transmission priority or whether to transmit corresponding video data according to the degree of importance, when the amount of the video data to be transmitted per unit time exceeds the bandwidth of a transmission channel.
It is another object of the present invention to provide a wireless receiving system for receiving video packet data which includes the degree of importance of the video packet data and for decoding the video packet data.
Accordingly, to achieve the first object, in one embodiment, there is provided a wireless, transmission system for transmitting a video packet through a wireless channel, the wireless transmission system comprising a video encoder for encoding a video signal on a block-by-block basis, a degree of importance determiner for determining the degree of importance of video data encoded in each block from predetermined parameters, a data transmission determiner for determining the transmission priority or whether to transmit the encoded video data on the basis of at least the amount of encoded video data to be transmitted per unit time, the wireless channel conditions, and the degree of importance of the encoded video data, a video data packetizing unit for packetizing the video data determined to be transmitted, and a wireless transmitter for wirelessly transmitting packetized data.
In another embodiment, there is provided a wireless transmission system for. transmitting a video packet through a wireless channel, the wireless transmisson system comprising a video encoder for encoding a video signal on a block-by-block basis, a degree of importance determiner for determining the degree of importance of video data encoded in each block from predetermined parameters, a data transmission determiner for determining the transmission priority or whether to transmit the encoded video data on the basis of at least the amount of encoded video data to be transmitted per unit time, the wireless channel conditions, and the degree of importance of the encoded video data, a video and degree of importance data packetizing unit for packetizing the video data determined to be transmitted and inserting an information field which shows the degree of importance of the video data into a packet, and a wireless transmitter for wirelessly transmitting packetized data.
To achieve the second object, there is provided a wireless receiving system for receiving video packet data including an information field, in the packet data and recovering the received video packet data, wherein the information field shows the degree of importance of packet data, the wireless receiving system comprising a wireless receiver for receiving the packet data, a packet assembling unit for separating from the packet data the information field, which shows the degree of importance of the video data, extracting encoded video data, and assembling the extracted video data, and a weight video decoder for determining the complexity of a recovery method according to the degree of importance of the video data and recovering the assembled video data by the recovery method having the determined complexity.